Twin-to-twin “transfusion”. Twins who develop with some form of common circulation in utero may show a temporary difference of cutaneous color related to oddities of hemodynamics. In the figure, one sees twin neonates, of whom the one on the right is uniformly and abnormally erythematous, whereas the other is abnormally pallid. The one looks plethoric, the other, anemic. In the course of time, restoration of normal blood counts and color will develop in both.